1. Field of the Invention
The present invention is directed to adhesive coated sheet materials and especially those in the form of tapes, strips, lables or the like. In particular, the invention is directed to such of those sheet materials as are intended generally for one-time use wherein they are bonded to themselves by contact between the adhesive surface and the opposite surface or back side or for multiple use as, for example, novelty stickers. Such adhesive coated sheet materials are well known, and provide means for restraining coiled, stacked or gathered items. Familiar examples include tape seal closures for rolls of postage stamps, banders for stacks of currency, skeins of yarn or shoestrings and the like. Due to the high value of many of these items, it is extremely important that the adhesive aggressively maintain the closure. On the other hand, the single use of such strips demands a cost consistent with disposability.
2. Description of the Prior Art
Published patents and literature descriptions of adhesive coated sheet materials are legion. It is also well known to use adhesive coated strips for the specific application of banding rolls of stamps, stacks of currency and the like. As above stated, this application demands a delicate balance between the strength and tack properties required to prevent premature release and the cost of the banders, themselves. The use of strps of conventional masking tape or a tape comprised of an uncoated Kraft base sheet having a conventional gum coating applied thereto have both proven unsatisfactory because the aggressive nature of the adhesive frequently resulted in the tape base sheet, itself, undesirably tearing or delaminating all around the strip, thus leaving the contents still banded. Attepts to modify such materials by providing selective coating of the adhesive to reduce the peel strength have proven costly. Other attempts to reduce the bonding by applying release coating to the back side have also been expensive. The use of an adhesive with less tack or bond strength is subject to premature adhesive failure. An alternative approach has been to increase the integrity of the base sheet to prevent delamination, but such stronger base sheets also increase costs and nonwoven base sheets require specially formulated adhesives or extended drying times. To merely illustrate this discussion of prior art adhesive coated materials, the following patents may be identified: U.S. Pat. No. 3,425,968 to Reiling date 4 Feb. 1969 directed to non-curling gummed products, U.S. Pat. No. 4,377,433 to Merz et al. dated 22 Mar. 1983, U.S. Pat. No. 2,978,343 to Russo et al. dated 4 Apr. 1961, U.S. Pat. No. 3,574,153 to Sirota dated 6 Apr. 1971, and U.S. Pat. No. 4,192,783 to Bomball et al. dated 11 Mar. 1980. These patents and conventional practice, however, reflect a standard procedure of applying the adhesive coating to uncoated base stock or to the uncoated side of coated base stock, thus leaving the coated side free for accepting printing. Both structures fail to satisfy the adhesive property requirements with ready release. U.S. Pat. No. 3,976,588 to Conway et al. dated 5 Feb. 1963 is directed to an adhesive construction requiring a smooth, film layer component.